Intel Pentium III Xeon (Tanner, Cascades) processors

Introduction: March 1999 (Tanner), October 1999 (Cascades)

Overview

The Xeon brand refers to many families of Intel's x86 multiprocessing CPUs - for dual-processor (DP) and multi-processor (MP) configuration on a single motherboard targeted at non-consumer markets of server and workstation computers, and also at blade servers and embedded systems. The Xeon brand has been maintained over several generations of x86 and x86-64 processors. Older models added the Xeon moniker to the end of the name of their corresponding desktop processor, but more recent models used the name Xeon on its own. The Xeon CPUs generally have more cache than their desktop counterparts in addition to multiprocessing capabilities. Intel's (non-x86) IA-64 processors are called Itanium, not Xeon.

The Tanner and Cascades cores

In 1999, the Pentium II Xeon was replaced by the Pentium III Xeon. Reflecting the incremental changes from the Pentium II "Deschutes" core to the Pentium III "Katmai" core, the first Pentium III Xeon, named "Tanner", was just like its predecessor except for the addition of Streaming SIMD Extensions (SSE) and a few cache controller improvements. The second version, named "Cascades", was based on the Pentium III "Coppermine" core. The "Cascades" Xeon used a 133MT/s bus and relatively small 256KB on-die L2 cache resulting in almost the same capabilities as the Slot 1 Coppermine processors, which were capable of dual-processor operation but not quad-processor operation. To improve this situation, Intel released another version, officially also named "Cascades", but often referred to as "Cascades 2MB". That came in two variants: with 1MB or 2MB of L2 cache. Its bus speed was fixed at 100MT/s, though in practice the cache was able to offset this. Product codes for Tanner and Cascades mirrored that of Katmai and Coppermine; 80525 and 80526 respectively.